I largely agree with Mahons, in that while yes, scoring 7 points is initially equal to stopping 7 points, the rules give some advantages to the offense in terms of importance. Clock management is important, but also how an offense sets the tempo of a game. The best defenses in the league might be able to set the tempo of a game, but generally that is the offense's job. A run heavy team will chew up the clock, while a pass heavy team might run up the score so quickly that the opponent's offense becomes one dimensional without any input of the defense.
At the start of any given game, offense and defense are equally important (but even that's not quite true, maintaining the status quo results in a tie, and you need to score more than your opponent. It's not a huge difference in importance, but it's there). But here's the problem, defenses break down. All it takes is one drive, or even one play, for you to find yourself behind. Once you're behind, while defense is still important, they aren't equally important, because if you maintain the status quo, you lose. You MUST score 7+ points more than your opponent.
Now the flip-side is that if you're leading, logic would dictate that defense becomes more important, but most teams recognize that the inherent comparative disadvantage the defense is at can result in a large point swing quickly. Consider last week against the Boys, we were ahead 28-3 at the half, a 25 point margin, but ultimately only won by 7. When you are behind you MUST score, when you are tied, you MUST score, and when you lead you still SHOULD score.
That's the big thing that I think creates the difference, offense has a wider margin of error than defense, and that margin of error difference makes scoring more often more important. Again, you don't neglect defense, but the tie-breaker probably goes to the offense.
And that doesn't even account for the fact that the inherent favoritism towards offense makes it easier for a team to schematically choose to build around offensive success as opposed to defensive success. Green Bay, New England, New Orleans, and 2010 and earlier Indianapolis are four examples, their offenses have been consistently great, while their defenses have fluctuated. Their scheme was/is based more on scoring than on stopping scores. Now, if you have an elite defense like Baltimore, you can get away with A LOT, and they represent sort of the flip-side in scheme building.
Think of it like this, would you rather win 100-99 or win 1-0. Both *should* be equally valid philosophies, but you almost never hold your opponent to 0, and you have to account for that. Even the best defenses fail at critical times, so having an offense is vital. There's an inherent push towards the 100-99 philosophy compared to the 1-0 philosophy because of the smaller margin of error that defenses have, which is compounded by the rules favoring the offense. That's on top of the fact that an offense can control the tempo of the game.and clock management. A lot of teams just sort of decide that if they are going to have to score due to defensive failings, they might as well score A LOT, and dictate the game with their offense.